fileapi: Add modification time check for FileSystemFileStreamReader

webkit/fileapi/file_system_file_stream_reader.h

Index: webkit/fileapi/file_system_file_stream_reader.h
diff --git a/webkit/fileapi/file_system_file_stream_reader.h b/webkit/fileapi/file_system_file_stream_reader.h
index 219c1068f6f0fc2b20ef2edc1b8c86b4291964d5..2dc5162c4909c1c80a7eface81e67ddecd7fc8dd 100644
--- a/webkit/fileapi/file_system_file_stream_reader.h
+++ b/webkit/fileapi/file_system_file_stream_reader.h
@@ -8,7 +8,9 @@
 #include "base/bind.h"
 #include "base/memory/ref_counted.h"
 #include "base/platform_file.h"
+#include "base/time.h"
 #include "webkit/fileapi/file_system_url.h"
+#include "webkit/fileapi/fileapi_export.h"
 #include "webkit/blob/file_stream_reader.h"
 #include "webkit/blob/shareable_file_reference.h"
 
@@ -30,12 +32,18 @@ class FileSystemContext;
 // filesystems but remote filesystem should implement its own reader
 // rather than relying on FileSystemOperation::GetSnapshotFile() which
 // may force downloading the entire contents for remote files.
-class FileSystemFileStreamReader : public webkit_blob::FileStreamReader {
+class FILEAPI_EXPORT_PRIVATE FileSystemFileStreamReader
+    : public webkit_blob::FileStreamReader {
  public:
   // Creates a new FileReader for a filesystem URL |url| form |initial_offset|.
+  // |expected_modification_time| specifies the expected last modification if
+  // the value is non-null, the reader will check the underlying file's actual
+  // modification time to see if the file has been modified, and if it does any
+  // succeeding read operations should fail with ERR_UPLOAD_FILE_CHANGED error.
   FileSystemFileStreamReader(FileSystemContext* file_system_context,
                              const FileSystemURL& url,
-                             int64 initial_offset);
+                             int64 initial_offset,
+                             const base::Time& expected_modification_time);
   virtual ~FileSystemFileStreamReader();
 
   // FileStreamReader overrides.
@@ -58,6 +66,7 @@ class FileSystemFileStreamReader : public webkit_blob::FileStreamReader {
   scoped_refptr<FileSystemContext> file_system_context_;
   FileSystemURL url_;
   const int64 initial_offset_;
+  const base::Time expected_modification_time_;
   scoped_ptr<webkit_blob::LocalFileStreamReader> local_file_reader_;
   scoped_refptr<webkit_blob::ShareableFileReference> snapshot_ref_;
   bool has_pending_create_snapshot_;